Our studies are directed towards an analysis of the composition of several RNA containing animal viruses (vesicular stomatitis virus (VSV), poliovirus and Friend leukemia virus (FLV), their replication and assembly in infected permissive and non-permissive host cells. We are also studying the interaction of host cell and virus; i.e., the block in VSV replicaton in non-permissive human lymphoblastoid cells, and the alteration of VSV and Friend virus envelope proteins and glycoproteins dictated by host cell processing. We are examining in vivo and in vitro protein synthesis in VSV infected cells and cytoplasmic extracts to determine the precise number of virus specific gene products, their processing and assembly into mature virions and their interaction with host cell membranes during maturation.